Haemolytic Disease of the Fetus and Newborn (HDFN) is caused by maternal alloimmunization against red blood cell antigens. In severe cases, HDFN may lead to fetal anaemia with a risk for fetal death ...and to severe forms of neonatal hyperbilirubinaemia with a risk for kernicterus. Most severe cases are caused by anti‐D, despite the introduction of antental and postnatal anti‐D immunoglobulin prophylaxis. In general, red blood cell antibody screening programmes are aimed to detect maternal alloimmunization early in pregnancy to facilitate the identification of high‐risk cases to timely start antenatal and postnatal treatment. In this review, an overview of the clinical relevance of red cell alloantibodies in relation to occurrence of HDFN and recent views on prevention, screening and treatment options of HDFN are provided.
Most modern treatment protocols for acute lymphoblastic leukaemia (ALL) include the analysis of minimal residual disease (MRD). To ensure comparable MRD results between different MRD-polymerase chain ...reaction (PCR) laboratories, standardization and quality control are essential. The European Study Group on MRD detection in ALL (ESG-MRD-ALL), consisting of 30 MRD-PCR laboratories worldwide, has developed guidelines for the interpretation of real-time quantitative PCR-based MRD data. The application of these guidelines ensures identical interpretation of MRD data between different laboratories of the same MRD-based clinical protocol. Furthermore, the ESG-MRD-ALL guidelines will facilitate the comparison of MRD data obtained in different treatment protocols, including those with new drugs.
Most current treatment protocols for acute lymphoblastic leukemia (ALL) include minimal residual disease (MRD) diagnostics, generally based on PCR analysis of rearranged antigen receptor genes. ...Although flow cytometry (FCM) can be used for MRD detection as well, discordant FCM and PCR results are obtained in 5-20% of samples. We evaluated whether 6-color FCM, including additional markers and new marker combinations, improved the results. Bone marrow samples were obtained from 363 ALL patients at day 15, 33 and 78 and MRD was analyzed using 6-color (218 patients) or 4-color (145 patients) FCM in parallel to routine PCR-based MRD diagnostics. Compared with 4-color FCM, 6-color FCM significantly improved the concordance with PCR-based MRD data (88% versus 96%); particularly the specificity of the MRD analysis improved. However, PCR remained more sensitive at levels <0.01%. MRD-based risk groups were similar between 6-color FCM and PCR in 68% of patients, most discrepancies being medium risk by PCR and standard risk by FCM. Alternative interpretation of the PCR data, aimed at prevention of false-positive MRD results, changed the risk group to standard risk in half (52%) of these discordant cases. In conclusion, 6-color FCM significantly improves MRD analysis in ALL but remains less sensitive than PCR-based MRD-diagnostics.
Response to therapy as determined by minimal residual disease (MRD) is currently used for stratification in treatment protocols for pediatric acute lymphoblastic leukemia (ALL). However, the large ...MRD-based medium risk group (MRD-M; 50-60% of the patients) harbors many relapses. We analyzed MRD in 131 uniformly treated precursor-B-ALL patients and evaluated whether combined MRD and IKZF1 (Ikaros zinc finger-1) alteration status can improve risk stratification. We confirmed the strong prognostic significance of MRD classification, which was independent of IKZF1 alterations. Notably, 8 of the 11 relapsed cases in the large MRD-M group (n=81; 62%) harbored an IKZF1 alteration. Integration of both MRD and IKZF1 status resulted in a favorable outcome group (n=104; 5 relapses) and a poor outcome group (n=27; 19 relapses), and showed a stronger prognostic value than each of the established risk factors alone (hazard ratio (95%CI): 24.98 (8.29-75.31)). Importantly, whereas MRD and IKZF1 status alone identified only 46 and 54% of the relapses, respectively, their integrated use allowed prediction of 79% of all the relapses with 93% specificity. Because of the unprecedented sensitivity in upfront relapse prediction, the combined parameters have high potential for future risk stratification, particularly for patients originally classified as non-high risk, such as the large group of MRD-M patients.
Anti-RhD immunised donors provide anti-RhD immunoglobulins used for the prevention of rhesus disease. These donors are periodically hyper-immunised (boostered) to retain a high titer level of ...anti-RhD.
We analysed anti-RhD donor records from 1998 to 2016, consisting of 30,116 anti-RhD titers from 755 donors, encompassing 3,372 booster events. Various models were fit to these data to allow describing the anti-RhD titers over time.
A random effects model with a log-linear anti-RhD titer decline over time and a saturating titer response to boostering is shown to fit the data well. This model contains two general model parameters, relating timing and maximum of the booster effect, as well as two parameters characterizing the individual donor, namely how fast the booster effect saturates with current titer and the anti-RhD decline rate. The average individual log2 decline is 0.55 per year, i.e. a 32% decline in absolute titer, with half of the donors declining between 13% and 41% per year. Their anti-RhD titer peaks around 26 days following a booster event. Boostering response reduces with higher titers at boostering; at median titer (log2 11) the mean increase per booster is log2 0.38, that is from an absolute titer of 2048 to 2665 (+30%), with half of all donors increasing between 16% and 65% in their titer.
The model describes anti-RhD titer change per individual with only four parameters, two of which are donor specific. This information can be used to enhance the blood bank's immunisation programme, by deriving individualized immunization policies in which boostering is adjusted to the anticipated anti-RhD decline, effectiveness of boostering and titer levels required.
BACKGROUND: Hemolytic disease of the fetus and newborn (HDFN) is a severe disease, resulting from maternal red cell (RBC) alloantibodies directed against fetal RBCs. The effect of a first‐trimester ...antibody screening program on the timely detection of HDFN caused by antibodies other than anti‐D was evaluated.
STUDY DESIGN AND METHODS: Nationwide, all women (1,002 in 305,000 consecutive pregnancies during 18 months) with alloantibodies other than anti‐D, detected by a first‐trimester antibody screen, were included in a prospective index‐cohort study. In a parallel‐coverage validation study, patients with HDFN caused by antibodies other than anti‐D, that were missed by the screening program, were retrospectively identified.
RESULTS: The prevalence of positive antibody screens at first‐trimester screening was 1,232 in 100,000; the prevalence of alloantibodies other than anti‐D was 328 in 100,000, of which 191 of 100,000 implied a risk for occurrence of HDFN because the father carried the antigen. Overall, severe HDFN, requiring intrauterine or postnatal (exchange) transfusions, occurred in 3.7 percent of fetuses at risk: for anti‐K in 11.6 percent; anti‐c in 8.5 percent; anti‐E in 1.1 percent; Rh antibodies other than anti‐c, anti‐D, or anti‐E in 3.8 percent; and for antibodies other than Rh antibodies or anti‐K, in none of the fetuses at risk. All affected children, where antibodies were detected, were promptly treated and healthy at the age of 1 year. The coverage validation study showed a sensitivity of the screening program of 75 percent. Five of 8 missed cases were caused by anti‐c, with delay‐induced permanent damage in at least 1.
CONCLUSION: First‐trimester screening enables timely treatment of HDFN caused by antibodies other than anti‐D, however, with a sensitivity of only 75 percent. A second screening at Week 30 of c– women will enhance the screening program. Severe HDFN, caused by antibodies other than anti‐D, is associated with anti‐K, anti‐c, and to a lesser extent with other Rh‐alloantibodies.
The contribution of genetic predisposing factors to the development of pediatric acute lymphoblastic leukemia (ALL), the most frequently diagnosed cancer in childhood, has not been fully elucidated. ...Children presenting with multiple de novo leukemias are more likely to suffer from genetic predisposition. Here, we selected five of these patients and analyzed the mutational spectrum of normal and malignant tissues. In two patients, we identified germline mutations in TYK2, a member of the JAK tyrosine kinase family. These mutations were located in two adjacent codons of the pseudokinase domain (p.Pro760Leu and p.Gly761Val). In silico modeling revealed that both mutations affect the conformation of this autoregulatory domain. Consistent with this notion, both germline mutations promote TYK2 autophosphorylation and activate downstream STAT family members, which could be blocked with the JAK kinase inhibitor I. These data indicate that germline activating TYK2 mutations predispose to the development of ALL.
Please cite this paper as: Kamphuis M, Paridaans N, Porcelijn L, De Haas M, van der Schoot C, Brand A, Bonsel G, Oepkes D. Screening in pregnancy for fetal or neonatal alloimmune thrombocytopenia: ...systematic review. BJOG 2010;117:1335–1343.
Background Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a potentially devastating disease, which may lead to intracranial haemorrhage (ICH), with neurological damage as a consequence. In the absence of screening, FNAIT is only diagnosed after bleeding symptoms, with preventive options limited to a next pregnancy.
Objectives To estimate the population incidence of FNAIT and its consequences to prepare for study design of a screening programme.
Search strategy An electronic literature search using MEDLINE, EMBASE and Cochrane database, and references of retrieved articles. No language restrictions were applied.
Selection criteria Prospective studies on screening for human platelet antigen 1a (HPA‐1a) alloimmunisation in low‐risk pregnant women.
Data collection and analysis Two reviewers independently assessed studies for inclusion and extracted data. Main outcome data were prevalence of HPA‐1a negativity, HPA‐1a immunisation, platelet count at birth and perinatal ICH. We aimed to compare outcome with and without intervention.
Main results HPA‐1a alloimmunisation occurred in 294/3028 (9.7%) pregnancies at risk. Severe FNAIT occurred in 71/227 (31%) immunised pregnancies, with perinatal ICH in 7/71 (10%). True natural history data were not found because interventions were performed in most screen‐positive women.
Authors’ conclusions Screening for HPA‐1a alloimmunisation detects about two cases in 1000 pregnancies. The calculated risk for perinatal ICH of 10% in pregnancies with severe FNAIT is an underestimation because studies without interventions were lacking. Screening of all pregnancies together with effective antenatal treatment such as intravenous immunoglobulin may reduce the mortality and morbidity associated with FNAIT.
Please cite this paper as: Scheffer P, van der Schoot C, Page‐Christiaens G, de Haas M. Noninvasive fetal blood group genotyping of rhesus D, c, E and of K in alloimmunised pregnant women: evaluation ...of a 7‐year clinical experience. BJOG 2011;118:1340–1348.
Objective To evaluate the diagnostic performance of noninvasive fetal blood group genotyping.
Design Descriptive analysis.
Setting Dutch national reference laboratory for pregnancies complicated by alloimmunisation.
Population All consecutive alloimmunised pregnant women for whom fetal blood group genotyping of rhesus D, c, E or of K in maternal plasma was performed from 2003 up to 2010.
Methods The test results of each individual assay were collected. Real‐time polymerase chain reaction was performed for RHD exon 5 and RHD exon 7, or the specific allele of the RHCE or KEL gene. A stringent diagnostic algorithm was applied. In the case of a negative result, the presence of fetal DNA was ascertained by the analysis of the Y chromosome‐specific SRY gene or other paternal genetic markers. Results were compared with available serology after birth or genotyping results of amniotic fluid cells.
Main outcome measures Percentage of conclusive test results and diagnostic accuracy.
Results A total of 362 tests was performed (D: n = 168; c: n = 49; E: n = 85; K: n = 60). The median gestational age was 17 weeks (range 7–38 weeks). In 351 women (97%), a test result was issued: in seven samples, the presence of fetal DNA could not be confirmed; in two samples, non‐specific amplification in the K assay led to an inconclusive result; in two samples, a maternal silent RHD gene prevented fetal RHD genotyping. No false‐positive or false‐negative results were found among those women for whom cord blood serology or genotyping results of amniotic fluid cells were available (n = 212).
Conclusions Noninvasive fetal blood group genotyping is accurate and applicable in a clinical diagnostic setting.
Immunoglobulin gene rearrangements are used as PCR targets for detection of minimal residual disease (MRD) in acute lymphoblastic leukemia (ALL). We investigated the occurrence of monoclonal ...immunoglobulin kappa-deleting element (IGK-Kde) rearrangements by Southern blotting and PCR/heteroduplex analysis at diagnosis, their stability at relapse, and their applicability in real-time quantitative PCR (RQ-PCR) analysis. In 77 selected children with precursor-B-ALL, Southern blotting detected 122 IGK-Kde rearrangements, 12 of which were derived from subclones in six patients (8%). PCR/heteroduplex analysis with BIOMED-1 Concerted Action primers identified 100 of the 110 major IGK-Kde rearrangements (91%). Comparison between diagnosis and relapse samples from 21 patients with PCR-detectable IGK-Kde rearrangements (using Southern blotting, PCR/heteroduplex analysis, and sequencing) demonstrated that 27 of the 32 rearrangements remained stable at relapse. When patients with oligoclonal IGK-Kde rearrangements were excluded, 25 of the 27 rearrangements remained stable at relapse and at least one stable rearrangement was present in 17 of the 18 patients. Subsequently, RQ-PCR analysis with allele-specific forward primers, a germline Kde TaqMan-probe, and a germline Kde reverse primer was evaluated for 18 IGK-Kde rearrangements. In 16 of the 18 targets (89%) a sensitivity of < or =10(-4) was reached. Analysis of MRD during follow-up of eight patients with IGK-Kde rearrangements showed comparable results between RQ-PCR data and classical dot-blot data. We conclude that the frequently occurring IGK-Kde rearrangements are generally detectable by PCR (90%) and are highly stable MRD-PCR targets, particularly where monoclonal rearrangements at diagnosis (95%) are concerned. Furthermore, most IGK-Kde rearrangements (90%) can be used for sensitive detection of MRD (< or =10(-4)) by RQ-PCR analysis.
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